Terminal and a method of controlling the same based on a state of the terminal

ABSTRACT

A first terminal configured to operate in conjunction with a second terminal, the first terminal including: a sensor configured to obtain information corresponding to a motion of the first terminal; a communicator configured to receive information corresponding to a motion of the second terminal from the second terminal; and a controller configured to, in response to a distance between the first terminal and the second terminal being greater than or equal to a critical value, control the communicator to transmit a notification message to the second terminal based on the information corresponding to the motion of the first terminal and the information corresponding to the motion of the second terminal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2014-0098646, filed on Jul. 31, 2014 in the Korean IntellectualProperty Office, Korean Patent Application No. 10-2014-0152084, filed onNov. 4, 2014 in the Korean Intellectual Property Office, and KoreanPatent Application No. 10-2015-0052463, filed on Apr. 14, 2015 in theKorean Intellectual Property Office, the disclosures of which areincorporated herein in their entireties by reference.

BACKGROUND

1. Field

Aspects of one or more exemplary embodiments relate to terminals andmethods of controlling terminals, and more particularly, to methods inwhich terminals operate based on states between two or more terminals.

2. Description of the Related Art

As the types and sizes of terminals have varied, the number of usersusing a plurality of devices has increased. If a plurality of devicesare used, various user experiences may be provided based oncommunication between the plurality of devices. For example, a devicemay transmit a message to another device.

Various sensors may be arranged in a terminal. Using the varioussensors, the terminal may detect a state of the terminal and states ofan environment surrounding the terminal.

Accordingly, it is desirable to provide more useful functions andvarious user experiences to a user using a plurality of terminals.

SUMMARY

Provided are methods of controlling terminals to perform moreappropriate operations based on states of two terminals.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of one or more exemplary embodiments.

According to an aspect of an exemplary embodiment, there is provided afirst terminal configured to operate in conjunction with a secondterminal, the first terminal including: a sensor configured to obtaininformation corresponding to a motion of the first terminal; acommunicator configured to receive information corresponding to a motionof the second terminal from the second terminal; and a controllerconfigured to, in response to a distance between the first terminal andthe second terminal being greater than or equal to a critical value,control the communicator to transmit a notification message to thesecond terminal based on the information corresponding to the motion ofthe first terminal and the information corresponding to the motion ofthe second terminal.

The controller may be further configured to, in response to theinformation corresponding to the motion of the first terminal indicatingthat the first terminal is moving and the information corresponding tothe motion of the second terminal indicating that the second terminal isnot moving, control the communicator to transmit the notificationmessage to the second terminal.

The communicator may be further configured to perform a short-distancewireless communication with the second terminal, and the controller maybe further configured to determine the distance between the firstterminal and the second terminal based on an intensity of a signal usedfor the short-distance wireless communication detected by the firstterminal.

The communicator may be further configured to receive informationcorresponding to the distance between the first terminal and the secondterminal from the second terminal, and the controller may be furtherconfigured to determine the distance between the first terminal and thesecond terminal by correcting the received information corresponding tothe distance between the first terminal and the second terminal based onthe intensity of the detected signal.

The controller may be further configured to, in response to theinformation corresponding to the motion of the first terminal indicatingthat the first terminal is not moving and the information correspondingto the motion of the second terminal indicating that the second terminalis moving, switch an operation mode of the first terminal to a standbymode.

The controller may be further configured to, in response to the distancebeing greater than or equal to the critical value and the first terminalreceiving a designated input, control the communicator to transmit thenotification message to the second terminal.

According to an aspect of another exemplary embodiment, there isprovided a first terminal configured to operate in conjunction with asecond terminal, the first terminal including: a sensor configured toobtain information corresponding to a motion of the first terminal; acommunicator configured to receive information corresponding to a motionof the second terminal from the second terminal; a display configured todisplay a screen image; and a controller configured to, in response to adistance between the first terminal and the second terminal beinggreater than or equal to a critical value, control the display todisplay a notification message based on the information corresponding tothe motion of the first terminal and the information corresponding tothe motion of the second terminal.

The controller may be further configured to, in response to theinformation corresponding to the motion of the second terminalindicating that the second terminal is moving and the informationcorresponding to the motion of the first terminal indicating that thefirst terminal is not moving, control the display to display thenotification message.

The controller may be further configured to control the display todisplay the notification message based on a result of comparing a movingdirection of the first terminal indicated by the informationcorresponding to the motion of the first terminal to a moving directionof the second terminal indicated by the information corresponding to themotion of the second terminal.

According to an aspect of another exemplary embodiment, there isprovided a second terminal configured to operate in conjunction with afirst terminal, the second terminal including: a sensor configured toobtain information corresponding to a motion of the second terminal; acommunicator configured to transmit the information corresponding to themotion of the second terminal to the first terminal and to receiveinformation corresponding to an operation from the first terminal, theoperation being determined based on the information corresponding to themotion of the second terminal; and a controller configured to perform anoperation determined based on the received information.

According to an aspect of another exemplary embodiment, there isprovided a method of controlling a first terminal capable of operatingin conjunction with a second terminal, the method including: obtaininginformation corresponding to a motion of the first terminal; receivinginformation corresponding to a motion of the second terminal from thesecond terminal; and transmitting, in response to a distance between thefirst terminal and the second terminal being greater than or equal to acritical value, a notification message to the second terminal based onthe information corresponding to the motion of the first terminal andthe information corresponding to the motion of the second terminal.

The transmitting may include transmitting the notification message tothe second terminal in response to the information corresponding to themotion of the first terminal indicating that the first terminal ismoving and the information corresponding to the motion of the secondterminal indicating that the second terminal is not moving.

The method may further include: performing a short-distance wirelesscommunication with the second terminal; and determining the distancebetween the first terminal and the second terminal based on an intensityof a signal used for the short-distance wireless communication detectedby the first terminal.

The transmitting may include transmitting the notification message tothe second terminal in response to the determined distance being greaterthan or equal to the critical value.

The method may further include receiving information corresponding tothe distance between the first terminal and the second terminal from thesecond terminal.

The determining the distance may include correcting the receivedinformation corresponding to the distance between the first terminal andthe second terminal based on the intensity of the detected signal.

The method may further include switching, in response to the informationcorresponding to the motion of the first terminal indicating that thefirst terminal is not moving and the information corresponding to themotion of the second terminal indicating that the second terminal ismoving, an operation mode of the first terminal to a standby mode.

The transmitting may include transmitting the notification message tothe second terminal in response to the distance being greater than orequal to the critical value and the first terminal receiving adesignated input.

According to an aspect of another exemplary embodiment, there isprovided a method of controlling a first terminal capable of operatingin conjunction with a second terminal, the method including: obtaininginformation corresponding to a motion of the first terminal; receivinginformation corresponding to a motion of the second terminal from thesecond terminal; and, outputting, in response to a distance between thefirst terminal and the second terminal being greater than or equal to acritical value, a notification message based on the informationcorresponding to the motion of the first terminal and the informationcorresponding to the motion of the second terminal.

The outputting may include displaying the notification message inresponse to the information corresponding to the motion of the secondterminal indicating that the second terminal is moving and theinformation corresponding to the motion of the first terminal indicatingthat the first terminal is not moving.

The outputting may include displaying the notification message based ona result of comparing a moving direction of the first terminal indicatedby the information corresponding to the motion of the first terminal toa moving direction of the second terminal indicated by the informationcorresponding to the motion of the second terminal.

According to an aspect of another exemplary embodiment, there isprovided a method of controlling a second terminal capable of operatingin conjunction with a first terminal, the method including: obtaininginformation corresponding to a motion of the second terminal;transmitting the information corresponding to the motion of the secondterminal to the first terminal; receiving information corresponding toan operation from the first terminal, the operating being determinedbased on the information corresponding to the motion of the secondterminal; and performing the operation based on the receivedinformation.

According to an aspect of another exemplary embodiment, there isprovided a terminal including: a sensor configured to obtain informationcorresponding to a first state of the terminal; a communicator; and acontroller configured to: control the communicator to establish aconnection with another terminal, control the communicator to receiveinformation corresponding to a second state of the another terminal fromthe another terminal, and perform an operation based on the first stateand the second state.

The terminal may further include an input/output interface.

The controller may be further configured to control the input/outputinterface to output an audio signal.

The first state and the second state may indicate a change in a distancebetween the terminal and the another terminal, and the operation mayinclude increasing a volume of the output audio signal in response tothe first state and the second state indicating that the distance isincreasing and decreasing the volume of the output audio signal inresponse to the first state and the second state indicating that thedistance is decreasing.

The controller may be further configured to perform the operation basedon the first state and the second state in response to a distancebetween the terminal and the another terminal being greater than acritical value.

The controller may be further configured to determine the critical valuebased on at least one of environmental information detected by theterminal or environmental information detected by the another terminal.

The terminal may further include a luminance sensor.

The controller may be further configured to determine the critical valuebased on an amount of ambient light sensed by the luminance sensor.

The controller may be further configured to perform the operation basedon the first state and the second state in response to a distancebetween the terminal and the another terminal being greater than acritical value for a predetermined period of time.

The operation may include controlling the communicator to terminate theconnection.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of certain exemplaryembodiments, taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a block diagram of a first terminal according to an exemplaryembodiment;

FIG. 2 is a block diagram of the first terminal according to anexemplary embodiment;

FIG. 3 is a block diagram of a second terminal according to an exemplaryembodiment;

FIG. 4 is a block diagram of the second terminal according to anexemplary embodiment;

FIG. 5 is a flowchart showing a process of controlling the firstterminal according to an exemplary embodiment;

FIG. 6 is a timing diagram showing operations of the first terminal andthe second terminal according to an exemplary embodiment;

FIG. 7 is a timing diagram showing operations of the first terminal andthe second terminal, according to another exemplary embodiment;

FIG. 8 is a timing diagram showing operations of the first terminal andthe second terminal, according to another exemplary embodiment;

FIG. 9 is a diagram for describing a method by which the first terminaland the second terminal communicate with each other, according to anexemplary embodiment;

FIG. 10 is a diagram for describing a method by which the first terminaland the second terminal communicate with each other, according toanother exemplary embodiment;

FIG. 11 is a diagram for describing a method by which the first terminaland the second terminal communicate with each other, according toanother embodiment;

FIGS. 12 through 14 are diagrams for describing operations of the firstterminal and the second terminal, according to an exemplary embodiment;

FIGS. 15A and 15B are diagrams for describing operations determinedbased on a first state and a second state;

FIG. 16 is a flowchart for describing a process in which a firstterminal performs an operation based on a first state and a secondstate, according to an exemplary embodiment;

FIG. 17 is a flowchart for describing a process in which a firstterminal performs an operation, according to another exemplaryembodiment;

FIG. 18 is a flowchart for describing a process of performing anoperation determined based on feedback information regarding anoperation performed by a first terminal, according to an exemplaryembodiment;

FIG. 19 is a flowchart showing a process in which a first terminalperforms an advanced synchronization, according to an exemplaryembodiment;

FIG. 20 is a schematic diagram showing the first terminal performing anadvanced synchronization, according to an exemplary embodiment;

FIG. 21 is a flowchart showing a process of performing an advancedsynchronization, according to another exemplary embodiment;

FIG. 22 is a diagram for describing the execution of an advancedsynchronization according to an exemplary embodiment;

FIG. 23 is a flowchart showing a process of displaying a notificationmessage on the second terminal, according to an exemplary embodiment;

FIGS. 24 through 26 are diagrams for describing examples of displayingnotification messages on the second terminal, according to variousexemplary embodiments;

FIG. 27 is a flowchart showing a process in which the first terminaltransmits a notification message to the second terminal, according to anexemplary embodiment;

FIG. 28 is a diagram for describing an example that the first terminaltransmits a notification message, according to an exemplary embodiment;

FIG. 29 is a flowchart showing a process in which the first terminaloperates, according to another exemplary embodiment;

FIGS. 30 through 33 are diagrams showing methods of using the firstterminal and the second terminal for lost child prevention according tovarious exemplary embodiments;

FIG. 34 is a flowchart showing a process in which the first terminaloperates, according to another exemplary embodiment;

FIGS. 35 through 38 are diagram showings a method of using a firstterminal and a second terminal for lost child prevention, according tovarious exemplary embodiments;

FIG. 39 is a flowchart showing a process of displaying a notificationmessage on the second terminal, according to another exemplaryembodiment;

FIGS. 40 and 41 are diagrams for describing an example that the secondterminal displays a notification message, according to various exemplaryembodiments.

DETAILED DESCRIPTION

Hereinafter, certain exemplary embodiments will be described more fullywith reference to the accompanying drawings. Exemplary embodiments may,however, be embodied in many different forms and should not be construedas limited to the certain exemplary embodiments set forth herein.Rather, the certain exemplary embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of one or more exemplary embodiments to those skilled in the art.In drawings, certain elements are omitted for clarity, and likereference numerals denote like elements throughout the specification.Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

Throughout the specification, it will be understood that when a portionis referred to as being “connected to” another portion, it can be“directly connected to” the other portion or “electrically connected to”the other portion via another element. Furthermore, it will be furtherunderstood that the terms “includes,” “including,” “comprises,” and/or“comprising” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

Hereinafter, certain exemplary embodiments will be described in detailwith reference to accompanying drawings.

FIG. 1 is a block diagram of a first terminal 100 according to anexemplary embodiment.

As shown in FIG. 1, the first terminal 100 may include a sensor 110,e.g., a sensor unit, a communicator 120, e.g., a communication unit, anda controller 130, e.g., a control unit. However, this is merely anexample, and the first terminal 100 may be embodied with more alternate,additional, or fewer components than the components shown in FIG. 1. Thefirst terminal 100 may be one of devices including a mobile phone, asmart phone, a tablet personal computer (PC), a laptop PC, an e-bookterminal, a digital multimedia broadcasting (DMB) terminal, a personaldigital assistant (PDA), a portable multimedia player (PMP), anavigation device, a TV, or a PC.

The sensor 110 may obtain first sensor information. The first sensorinformation refers to information regarding a state of the firstterminal 100 or a state of an environment surrounding the first terminal100, which is detected by the first terminal 100. For example, if thesensor 110 includes an acceleration sensor, the first sensor informationmay include an acceleration value generated as a physical motion of thefirst terminal 100 is detected. Configuration of the sensor 110 and thefirst sensor information may vary according to various exemplaryembodiments.

The communicator 120 may perform communication with a second terminal300 of FIG. 3. For example, if the first terminal 100 and the secondterminal 300 are located near each other, the communicator 120 maytransmit or receive data to or from the second terminal 300 by using ashort-distance wireless communication method. The communicator 120 mayreceive at least one of second sensor information and informationregarding a second state from the second terminal 300. The second sensorinformation may refer to information regarding a state of the secondterminal 300 or information regarding a state of an environmentsurrounding the second terminal 300, which is detected by the secondterminal 300. For example, second sensor information may include anacceleration value obtained by detecting a physical motion of the secondterminal 300 by using an acceleration sensor. The second state mayindicate a state of the second terminal 300. For example, the secondstate may indicate whether the second terminal 300 is moving or whethera user is using the second terminal 300.

The controller 130 may control respective components of the firstterminal 100 and process information for process operations of the firstterminal 100. The controller 130 may determine a first state based onfirst sensor information. The first state may indicate a state of thefirst terminal 100. For example, the first state may indicate whetherthe first terminal 100 is moving or whether a user is using the firstterminal 100. Furthermore, the controller 130 may determine a secondstate. The second state may be a state of the second terminal 300. Whensecond sensor information is received by the communicator 120, thecontroller 130 may determine the second state based on the receivedsecond sensor information. Alternatively, if information regarding thesecond state is received by the communicator 120, the controller 130 maydetermine the second state based on the received information.

Furthermore, the controller 130 may determine a distance between thefirst terminal 100 and the second terminal 300. According to anexemplary embodiment, a distance between the first terminal 100 and thesecond terminal 300 may be determined based on a received signalstrength indicator (RSSI) of a wireless frequency signal received by thecommunicator 120. For example, if an RSSI is from about −100decibel-milliwatts (dBm) to about −80 dBm, the controller 130 maydetermine that the distance between the first terminal 100 and thesecond terminal 300 is about 2 m. Furthermore, as an RSSI becomesstronger, the controller 130 may determine that the distance between thefirst terminal 100 and the second terminal 300 decreases.

According to an exemplary embodiment, the communicator 120 may receiveinformation regarding a distance between the first terminal 100 and thesecond terminal 300 from the second terminal 300. The informationregarding the distance received from the second terminal 300 may includeinformation regarding an RSSI detected by the second terminal 300 or adistance determined by the second terminal 300. The controller 130 maydetermine a more accurate distance by further reflecting informationregarding a distance received from the second terminal 300. For example,the controller 130 may determine a distance between the first terminal100 and the second terminal 300 based on an average RSSI, a distancedetected by the first terminal 100, and an RSSI or a distance detectedby the second terminal 300.

Furthermore, the controller 130 may determine an operation to performbased on both the first state and the second state and the distancebetween the first terminal 100 and the second terminal 300.Alternatively, the controller 130 may determine an operation to performbased on one of the first state and the second state and the distancebetween the first terminal 100 and the second terminal 300.

The controller 130 may perform a determined operation by controllingcomponents of the first terminal 100. The determined operation may referto a function that may be provided by the first terminal 100. Forexample, the determined operation may be displaying a message,transmitting information to another device, or switching an operationmode of the first terminal 100.

FIG. 2 is a block diagram of the first terminal 100 according to anexemplary embodiment. However, this is merely an example, and the firstterminal 100 may be embodied with alternate, additional, or fewercomponents than shown in FIG. 2.

Referring to FIG. 2, the first terminal 100 may include the sensor 110,the communicator 120, the controller 130, a GPS device 140, e.g., a GPSmodule or GPS, a camera 150, e.g., a camera module, an input/outputinterface 160, e.g., an input/output module or a user interface, astorage 170, e.g., a storage unit, and a power supply 180, e.g., a powersupply unit. The communicator 120 may include at least one of a mobilecommunicator 121, e.g., a mobile communication module, a subcommunicator 122, e.g., a sub communication module, and a multimediamodule 123. The sub communicator 122 may include at least one of awireless LAN module 122-1 and a short-distance wireless communicator122-2, e.g., a short-distance wireless communication module. Themultimedia module 123 may include at least one of a broadcastingcommunicator 123-1, e.g., a broadcasting communication module, an audioplayback module 123-2, and a moving picture playback module 123-3.

The sensor 110 may include at least one sensor. For example, a sensormodule may include at least one of an acceleration sensor, a geomagneticsensor, a gyro sensor, a heart rate sensor, a proximity sensor, aluminance sensor, a touch sensor, a fingerprint sensor, an iris sensor,a blood pressure sensor, a temperature sensor, a muscle sensor, anatmospheric pressure sensor, a blood sugar sensor, a brain wave sensor,and a humidity sensor. The acceleration sensor refers to a sensorcapable of detecting an acceleration applied to the first terminal 100.The geomagnetic sensor may detect a direction of a geomagnetic fielddetected at the location of the first terminal 100. The gyro sensor maydetect a rotating motion of the first terminal 100. The heart ratesensor may detect the heart rate of a user. The proximity sensor maydetect a distance that an object is apart from the proximity sensor. Theluminance sensor may detect the intensity of ambient light around thefirst terminal 100. The touch sensor may detect a contact of a touchmaterial (e.g., a finger), and a location of the detected contact. Thefingerprint sensor may detect information regarding a fingerprint of auser. The iris sensor may detect information regarding an iris of auser. The blood pressure sensor may detect a blood pressure of a user.The temperature sensor may detect a temperature inside or outside thefirst terminal 100. The muscle sensor may detect a movement of a muscle.The atmospheric pressure sensor may detect an atmospheric pressurearound the first terminal 100. The blood sugar sensor may detect anamount of blood sugar included in blood, e.g., a blood sample. The brainwave sensor may detect a brain wave of a user by using, for example, anelectrode or the like. The humidity sensor may detect humidity aroundthe first terminal 100.

The communicator 120 may be connected to the second terminal 300 or anexternal device, such as an external server, by using at least one ofthe mobile communicator 121, the sub communicator 122, and themultimedia module 123.

The mobile communicator 121 may be controlled by the controller 130 toconnect the first terminal 100 to an external device via a mobilecommunication using at least one or more antennas. The mobilecommunicator 121 may transmit/receive wireless signals for a voice call,a video call, a short message service (operation SMS), or a multimediamessage service (MMS) to/from a mobile phone, a smart phone, a tabletPC, or any of various other devices corresponding to a phone numberinput to the first terminal 100.

The sub communicator 122 may include at least one of the wireless LANmodule 122-1 and the short-distance wireless communicator 122-2. The subcommunicator 122 may include only the wireless LAN module 122-1, onlythe short-distance wireless communicator 122-2, or both the wireless LANmodule 122-1 and the short-distance wireless communicator 122-2.

The wireless LAN module 122-1 may be connected to a network, such as theInternet, or another device at a location where an access point (AP) isinstalled, under the control of the controller 130. The wireless LANmodule 122-1 may support the wireless LAN specification (IEEE 802.11x)of the Institute of Electrical and Electronics Engineers (IEEE). Theshort-distance wireless communicator 122-2 may perform short-distancewireless communication between the first terminal 100 and the secondterminal 300 under the control of the controller 130. Wirelessshort-distance wireless communication methods may include Bluetooth™,infrared data association (IrDA), near field communication (NFC), orZigBee.

According to an exemplary embodiment, the controller 130 may determine adistance between the first terminal 100 and the second terminal 300based on an RSSI of a wireless frequency signal received by theshort-distance wireless communicator 122-2. For example, the secondterminal 300 may generate a wireless frequency signal for a wirelessshort-distance wireless communication of a pre-set intensity (e.g., 21dB), and the first terminal 100 may measure intensity of a receivedwireless frequency signal. The controller 130 of the first terminal 100may determine a distance d between the first terminal 100 and the secondterminal 300 according to Equation 1 below based on the measuredintensity of the wireless frequency signal.

$\begin{matrix}{d = {{\frac{\lambda}{4\pi} \cdot 10^{\frac{L}{20}}} = {\frac{c}{4\pi\; f} \cdot 10^{\frac{L}{20}}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In equation 1, c denotes a propagation rate, f denotes a frequency, andL denotes a loss of signal intensity. The propagation rate of a wirelesssignal in the air has a constant value. The frequency is a frequencydesignated for performing a short-distance wireless communication.Furthermore, the loss of signal intensity may be obtained based on adifference between the intensity of a wireless frequency signalgenerated by the second terminal 300 and intensity of a receivedwireless frequency signal. Therefore, the controller 130 may determinethe distance d between the first terminal 100 and the second terminal300 according to Equation 1 above.

Based on the performance of the first terminal 100, the first terminal100 may include at least one of the mobile communicator 121, the subcommunicator 122, and the short-distance wireless communicator 122-2.

The multimedia module 123 may include at least one of the broadcastingcommunicator 123-1, the audio playback module 123-2, and the movingpicture playback module 123-3. The broadcasting communicator 123-1 mayreceive a broadcasting signal (e.g., a TV broadcasting signal, a radiobroadcasting signal, or a data broadcasting signal) and additionalbroadcasting information (e.g., an electric program guide (EPG) or anelectric service guide (ESG)) transmitted by a broadcasting station viaa broadcasting communication antenna, under the control of thecontroller 130. The audio playback module 123-2 may playback a stored orreceived digital audio file under the control of the controller 130. Themoving picture playback module 123-3 may playback a digital movingpicture file, e.g., a video file.

The multimedia module 123 may not include the broadcasting communicator123-1, but may only include the audio playback module 123-2 and themoving picture playback module 123-3. Furthermore, the audio playbackmodule 123-2 or the moving picture playback module 123-3 may be includedin the controller 130.

The controller 130 may include a central processing unit (CPU) 131,read-only memory (ROM) 132 having stored therein a control program forcontrolling the first terminal 100, and random-access memory (RAM) 133,which stores a signal or data output from outside the first terminal 100or is used as a memory space in the first terminal 100 so as to performa task. The CPU 131 may include a single core or a plurality of cores,may be a single core, dual core (two cores), triple core (three cores),and quad cores (four cores) processor. The CPU 131, the ROM 132, and theRAM 133 may be connected to one another via an internal bus.

The controller 130 may control the communicator 120, the camera 150, theGPS device 140, the input/output interface 160, the sensor 110, thestorage 170, the power supply 180, and a display 190, e.g., a displayunit.

The GPS device 140 may receive radio wave signals from a plurality ofGPS satellites on the Earth's orbit and calculate a location of thefirst terminal 100 based on a time that a signal arrives from the GPSsatellites at the first terminal 100.

The input/output interface 160 may include at least one of a button 161,a microphone 162, a speaker 163, a vibration motor 164, a connector 165,and a keypad 166.

The button 161 may be formed on the front surface, side surfaces, or therear surface of the housing of the first terminal 100 and may include atleast one of a power/lock button, a volume button, a menu button, a homebutton, a back button, and a search button.

The microphone 162 may receive a voice or a sound and generate anelectric signal under the control of the controller 130.

The speaker 163 may output sounds corresponding to various signalsreceived from the mobile communicator 121, the sub communicator 122, themultimedia module 123, or the camera 150.

The vibration motor 164 may transform an electric signal to a mechanicalvibration under the control of the controller 130. For example, when thefirst terminal 100 set to a vibration mode receives a voice call fromanother device, the vibration motor 164 may be operated. If the display190 includes a touch screen, the vibration motor 164 may be operated inresponse to a user touch on the touch screen or successive motions of atouch input on the touch screen.

The connector 165 may be used as an interface for interconnecting thefirst terminal 100 and an external device or a power source. Under thecontrol of the controller 130, data stored in the storage 170 of thefirst terminal 100 may be transmitted to an external device or data maybe received from an external device via a cable connected to theconnector 165. Power may be input from a power source, or a battery maybe charged via a cable connected to the connector 165.

The keypad 166 may receive a key input for controlling the firstterminal 100 from a user. The keypad 166 may include a physical keypadformed at the first terminal 100, or a virtual keypad displayed at thedisplay 190. A physical keypad formed at the first terminal 100 may beomitted according to performance or structure of the first terminal 100.

The storage 170 may store signals or data input/output in correspondenceto operations of the mobile communicator 121, the sub communicator 122,the multimedia module 123, the camera 150, the GPS device 140, theinput/output interface 160, the sensor 110, and the display 190, underthe control of the controller 130. The storage 170 may store controlprograms and applications for controlling the first terminal 100 or thecontroller 130.

The term “storage” may include the storage 170, the ROM 132 and the RAM133 in the controller 130, or a memory card attached to the firstterminal 100. The storage 170 may include a non-volatile memory, avolatile memory, a hard disk drive (HDD), or a solid state drive(operation SSD).

The power supply 180 may supply power to at least one battery arrangedin the housing of the first terminal 100, under the control of thecontroller 130. Furthermore, the power supply 180 may supply power,which is input from an external power source via a cable connected tothe connector 165, to the respective components of the first terminal100.

The display 190 may output user interfaces and information correspondingto various services to a user. The display 190 may include a liquidcrystal display (LCD), a plasma display panel (PDP), a transparentdisplay, or a flexible display capable of displaying an image.Furthermore, the display 190 may include a touch screen. A touch screenmay generate an analog signal corresponding to at least one touch inputto a user interface. A touch screen may receive at least one touch inputvia a body part of a user (e.g., a finger) or a touch input unit (e.g.,a stylus pen). A touch screen may receive successive motions of at leastone touch input.

A touch input is not limited to an input based on a contact between atouch screen and a body part of a user or a touch input unit and mayinclude a non-contact input (e.g., an input based on a distance betweena touch screen and a body part being less than or equal to 1 mm). Adistance that may be detected by a touch screen may vary according toone or more exemplary embodiments of the first terminal 100. A touchscreen may be embodied as a resistive type, a capacitive type, aninfrared type, or an ultrasound wave type.

The display 190 may transform an analog signal generated by a touchscreen into a digital signal (e.g., an X coordinate and a Y coordinate)and transmit the digital signal to the controller 130. The controller130 may receive a digital signal, which is received from the display190, as a user input.

FIG. 3 is a block diagram of the second terminal 300 according to anexemplary embodiment.

As shown in FIG. 3, the second terminal 300 may include the sensor 310,the communicator 320, and the controller 330. However, according to oneor more exemplary embodiments, the second terminal device 300 mayinclude alternate or additional components, or may not include all ofthe components shown in FIG. 3. The second terminal 300 may be, asnon-limiting examples, a wearable device, such as a smart watch andsmart glasses, a mobile phone, a smart phone, a tablet PC, a laptop PC,an e-book terminal, a digital multimedia broadcasting (DMB) terminal, apersonal digital assistant (PDA), a portable multimedia player (PMP), anavigation device, a TV, or a PC.

The sensor 310 may obtain second sensor information. The second sensorinformation refers to information regarding a state of the secondterminal 300 or a state of an environment surrounding the secondterminal 300, which is detected by the second terminal 300. For example,if the sensor 310 includes an acceleration sensor, the second sensorinformation may include an acceleration value generated as a physicalmotion of the second terminal 300 is detected. Configuration of thesensor 310 and the second sensor information may vary according tovarious exemplary embodiments.

The communicator 320 may perform communication with the first terminal100 of FIG. 1. For example, if the first terminal 100 and the secondterminal 300 are located near each other, the communicator 320 maytransmit or receive data to or from the first terminal 100 by using ashort-distance wireless communication method. The communicator 320 maytransmit at least one of second sensor information and informationregarding a second state to the first terminal 100. The second sensorinformation may refer to information regarding a state of the secondterminal 300 or information regarding a state of an environmentsurrounding the second terminal 300, which is detected by the secondterminal 300. For example, second sensor information may include anacceleration value obtained by detecting a physical motion of the secondterminal 300 by using an acceleration sensor. The second state mayindicate a state of the second terminal 300. For example, the secondstate may indicate whether the second terminal 300 is moving or whethera user is using the second terminal 300.

The controller 130 may control respective components of the secondterminal 300 and process information for the second terminal 300 toprocess operations. According to an exemplary embodiment, the controller330 may determine a second state based on the second sensor information.The second state may indicate a state of the second terminal 300. Forexample, the second state may indicate whether the second terminal 300is moving or whether a user is using the second terminal 300. Accordingto another exemplary embodiment. The second terminal 300 may transmitthe second sensor information obtained via the sensor 310 to the firstterminal 100 or an external server as raw data via the communicator 320,and the first terminal 100 or the external server which receives thesecond sensor information may determine the second state.

Furthermore, the controller 330 may determine a distance between thefirst terminal 300 and the second terminal 300. According to anexemplary embodiment, a distance between the first terminal 300 and thesecond terminal 300 may be determined based on a received signalstrength indicator (RSSI) of a wireless frequency signal received by thecommunicator 320. For example, if an RSSI is from about −100 dBm toabout −80 dBm, the controller 330 may determine that the distancebetween the first terminal 300 and the second terminal 300 is about 2 m.Furthermore, if an RSSI becomes stronger, the controller 330 maydetermine that the distance between the first terminal 300 and thesecond terminal 300 decreases. The communicator 320 may transmitinformation regarding the distance between the first terminal 100 andthe second terminal 300 determined by the controller 330 to the firstterminal 100.

Furthermore, the communicator 320 may receive information regarding anoperation, which is determined based on the information regarding thesecond state transmitted to the second terminal 300, from the firstterminal 100. As the information regarding the operation determinedbased on the information regarding the second state is received, thecontroller 330 may perform an operation corresponding to the receivedinformation. For example, if an alarm message is received from the firstterminal 100, the second terminal 300 may output the received alarmmessage.

FIG. 4 is a block diagram of the second terminal 300 according to anexemplary embodiment. The second terminal 300 may be embodied withadditional, alternate, or fewer components than the components shown inFIG. 4.

Referring to FIG. 4, the second terminal 300 may include the sensor 310,the communicator 320, the controller 330, a GPS device 340, a camera350, an input/output interface 360, a storage 370, and a power supply380. The communicator 320 may include at least one of a mobilecommunicator 321, a sub communicator 322, and a multimedia module 323.The sub communicator 322 may include at least one of a wireless LANmodule 322-1 and a short-distance wireless communicator 322-2. Themultimedia module 323 may include at least one of a broadcastingcommunicator 323-1, an audio playback module 323-2, and a moving pictureplayback module 323-3. The input/output interface 360 may include atleast one of a button 361, a microphone 362, a speaker 363, a vibrationmotor 364, a connector 365, and a keypad 366.

The sensor 310 may include at least one sensor. For example, a sensormodule may include at least one of an acceleration sensor, a geomagneticsensor, a gyro sensor, a heart rate sensor, a proximity sensor, aluminance sensor, a touch sensor, a fingerprint sensor, an iris sensor,a blood pressure sensor, a temperature sensor, a muscle sensor, anatmospheric pressure sensor, a blood sugar sensor, a brain wave sensor,and a humidity sensor.

The multimedia module 323 may include at least one of the broadcastingcommunicator 323-1, the audio playback module 323-2, and the movingpicture playback module 323-3.

The controller 330 may include a CPU 331, ROM 332 having stored thereina control program for controlling the second terminal 300, and RAM 333,which stores a signal or data output from outside the second terminal300 or is used as a memory space in the second terminal 300 so as toperform a task.

The various components of the second terminal 300 may have similarstructures and functions to the corresponding components of the firstterminal device 100 described with reference to FIG. 2.

FIG. 5 is a flowchart showing a process of controlling the firstterminal 100 according to an exemplary embodiment.

First, the first terminal 100 may establish communication, e.g., aconnection, with the second terminal 300. For example, the firstterminal 100 may be paired with the second terminal 300 to performBluetooth communication with the second terminal 300. A ‘paired state’may refer to a state in which two devices recognized each other forperforming communication.

The first terminal 100 may determine a first state indicating a state ofthe first terminal 100 (operation S510). In the operation S510, thefirst terminal 100 may obtain first sensor information by using a sensorand determine a first state corresponding to the first sensorinformation. For example, if the first sensor information includes anacceleration value, the controller 130 of the first terminal 100 maydetermine whether the first terminal 100 is moving based on theacceleration value. The controller 130 may determine the first state notonly based on an acceleration value corresponding to a time point atwhich the first state is determined, but also acceleration valuesaccumulated over a set time period. For example, if an average ofacceleration values for 10 seconds is greater than or equal to acritical value, the controller 130 may determine that the first terminal100 is moving.

Furthermore, the first terminal 100 may determine a second stateindicating a state of the second terminal 300 (operation S520). In theoperation S520, the first terminal 100 may receive second sensorinformation or information regarding the second state from the secondterminal 300. If the second sensor information is received from thesecond terminal 300, the first terminal 100 may determine the secondstate in a manner similar to that of the operation S510. Alternatively,if information regarding the second state is received, the firstterminal 100 may determine the second state without performing aseparate process of determining the second state. The first terminal 100may receive second sensor information as the second sensor informationis generated or may generate information regarding a second state thatis generated at a constant cycle. The first terminal 100 maycontinuously, quasi-continuously, regularly, periodically, orsporadically receive the second sensor information from the secondterminal 300.

The first state and the second state may indicate various states of thefirst terminal 100 and the second terminal 300 according to variousexemplary embodiments, respectively. For example, the first state andthe second state may indicate whether the first terminal 100 and thesecond terminal 300 are possessed by or worn by a moving user. Inanother example, the first state and the second state may also indicatewhether a person who owns the first terminal 100 and the second terminal300 is a driver or a passenger. For example, moving speeds of GPScoordinates of the first terminal 100 and the second terminal 300 may beincluded in a range indicating that a user is in a car. For example, ifthe second terminal 300 is a smart watch worn on a wrist, whether a useris a driver or a passenger may be determined based on whether a motiondetected by the second terminal 300 via the sensor 310 is a motion foroperating a steering wheel.

Next, the controller 130 of the first terminal 100 may perform anoperation determined based on at least one of a distance between thefirst terminal 100 and the second terminal 300, the determined firststate, and the determined second state (operation S530). The firstterminal 100 may determine the distance between the first terminal 100and the second terminal 300 by using various methods according tovarious exemplary embodiments. For example, the first terminal 100 maydetermine the distance between the first terminal 100 and the secondterminal 300 based on an RSSI of a wireless frequency signal used for ashort-distance wireless communication with the second terminal 300. Thefirst terminal 100 may improve accuracy of the determined distance byfurther reflecting distance information received from the secondterminal 300. In another example, the first terminal 100 may determinethe distance between the first terminal 100 and the second terminal 300by using a GPS coordinate of the first terminal 100 obtained by the GPSdevice 140 and a GPS coordinate of the second terminal 300 obtained bythe GPS device 340.

Operations to be performed by the first terminal 100 may vary accordingto various exemplary embodiments. According to another exemplaryembodiment, the first terminal 100 may provide a function for preventingloss of a terminal based on the operation performed in the operationS530. If the first terminal 100 is a smart phone and the second terminal300 is a wearable device, a loss/theft notification message may beprovided to a user as a distance between the first terminal 100 and thesecond terminal 300 becomes greater than or equal to a critical value.For example, if the first state indicates that the first terminal 100 isnot moving and the second state indicates that a user is wearing thesecond terminal 300 and the second terminal 300 is moving, the firstterminal 100 may determine that a user is moving and the first terminal100 was left behind. Therefore, as a distance between the first terminal100 and the second terminal 300 becomes greater than a critical value,the first terminal 100 may be set in a standby mode so as to reducepower consumption by the first terminal 100.

Furthermore, if the first state indicates that the first terminal 100 ismoving and the second state indicates that a user is wearing the secondterminal 300, the first terminal 100 may determine that, if a distancebetween the first terminal 100 and the second terminal 300 becomesgreater than a critical value, the first terminal 100 is stolen. Forexample, the second state may indicate that the second terminal 300,which is a wearable device, is worn by a user and is moving in adirection, whereas the first state may indicate that the first terminal100 is moving in another direction. In this case, if the distancebetween the first terminal 100 and the second terminal 300 becomesgreater than or equal to a critical value (e.g., 3 m), the firstterminal 100 may be determined to be stolen. In another example, thefirst state may be a result of analyzing motions of the first terminal100, whereas the second state may be a result of analyzing motions ofthe second terminal 300. If the second state indicates that the secondterminal 300, which is a wearable device, is not moving and the firststate indicates that a user of the first terminal 100 is walking, thefirst terminal 100 may be determined to be stolen. However, one or moreexemplary embodiments are not limited thereto.

If the first terminal 100 is determined to be stolen, the first terminal100 may transmit a theft notification message to the second terminal 300and may execute a data protection mode for protecting data stored in thefirst terminal 100.

The first state and the second state may also indicate whether a user iswalking or stopped. In this case, the first terminal 100 may determinewhether the user is walking by using a pattern regarding accelerationvalues, for example. For example, the first terminal 100 may determinewhether the user is walking based on a size, a direction, and a cycle ofrepeated acceleration values. In detail, if the first sensor informationor the second sensor information includes a pattern that similar changesof acceleration values are periodically repeated in an arbitrary sectionand a result of analysis regarding the entire arbitrary sectionindicates that the location of a terminal has changed, the firstterminal 100 may determine that a person possessing the first terminal100 or the second terminal 300 is walking. Furthermore, if the size of arepeating pattern and a speed at which the location of a terminal haschanged are greater than those corresponding to the case that the personpossessing the first terminal 100 or the second terminal 300 is walking,the first terminal 100 may determine that the person possessing thefirst terminal 100 or the second terminal 300 is running. However, oneor more exemplary embodiments are not limited thereto.

According to another exemplary embodiment, the first terminal 100 maydetermine an operation to perform based on a speed at which a distancebetween the first terminal 100 and the second terminal 300 is changedand perform the determined operation. For example, if a distance betweenthe first terminal 100 and the second terminal 300 increases at a speedgreater than or equal to a critical value, the first terminal 100 mayperform an operation for storing backup data or other operations forpreparing for a shock to the first terminal 100. In other words, if auser drops the first terminal 100, a distance between the first terminal100 and the second terminal 300 increases very fast. Therefore, in thiscase, the first terminal 100 may perform an operation corresponding to astate that the user dropped the first terminal 100. In another example,a distance between the first terminal 100 and the second terminal 300may rapidly increase, and the first state determined based on firstsensor information obtained via an acceleration sensor may indicate thata significant amount of shock is applied to the first terminal 100. Inthis case, the first terminal 100 may determine that the user droppedthe first terminal 100 and transmit a notification message notifyingthat the user dropped the first terminal 100 to the second terminal 300.The user may recognize that he or she dropped the first terminal 100based on the notification message displayed on the second terminal 300.Therefore, the user may be prevented from losing the first terminal 100.However, one or more exemplary embodiments are not limited thereto.

A critical value is not limited to a particular value, and a particularrange may also be referred to as a critical value. For example, acritical value may be 2 m, or a range from 1.5 m to 2.5 m may be acritical value.

Furthermore, a condition that a distance between two terminals isgreater than or equal to a critical value may include variousconditions. For example, a condition that a distance between twoterminals is greater than or equal to a critical value may include acondition that the signal intensity between the two terminals is lessthan or equal to a critical value. Furthermore, the condition that adistance between two terminals is greater than or equal to a criticalvalue may include a condition that a loss of signal intensity obtainedbased on a difference between the intensity of a wireless frequencysignal generated by the second terminal 300 and the intensity of areceived wireless frequency signal is greater than or equal to acritical value. In other words, even if a distance between two terminalsis not directly obtained based on a calculation, if the distance betweenthe two terminals is determined to be greater than or equal to acritical value based on variables (e.g., L of Equation 1) used forcalculating the distance between the two terminals, the determinationbased on the variables may be one for determining if the distancebetween the two terminals is greater than or equal to the criticalvalue.

According to another exemplary embodiment, the first terminal 100 mayprovide a function for preventing a child from being lost based on theoperation performed in the operation S530. If the second terminal 300 isa wearable device, a user may attach the second terminal 300 to a child,and the user, who is a parent of the child, may possess the firstterminal 100. If a distance between the first terminal 100 and thesecond terminal 300 is greater than a critical value and the secondstate indicates that the second terminal 300 is not moving, the firstterminal 100 may not perform any operation. However, if the first stateindicates that the first terminal 100 is not moving and the second stateindicates that the second terminal 300 is moving, the first terminal 100may output an alarm. Furthermore, if the first state and the secondstate indicate that the first terminal 100 and the second terminal 300are moving in different directions, the first terminal 100 may output analarm.

According to another exemplary embodiment, the first terminal 100 mayperform an advanced synchronization based on the operation performed inthe operation S530. The term ‘advanced synchronization’ may refer to anoperation in which the first terminal 100 continuously or periodicallyupdates a state of the second terminal 300. For example, if the firststate indicates that the first terminal 100 is not moving, the secondstate indicates that the second terminal 300 is moving, and a distancebetween the first terminal 100 and the second terminal 300 decreases toa distance less than a critical value, the first terminal 100 mayinitiate an advanced synchronization. In other words, as a userpossessing the second terminal 300 approaches to the stationary firstterminal 100, the first terminal 100 may initiate an advancedsynchronization. Alternatively, if the first state indicates that theuser possessing the second terminal 300 holds the first terminal 100 fora display of the first terminal 100 to face the user, the first terminal100 may initiate an advanced synchronization. Whether the user isholding the first terminal 100 may be determine based on whether a touchinput is received by a touch sensor of the first terminal 100.Furthermore, whether the user is holding the first terminal 100 suchthat the display of the first terminal 100 to face the user may bedetermined based on whether information regarding a rotation of thefirst terminal 100 detected via a gyro sensor is included in the firstsensor information. Alternatively, whether the user is holding the firstterminal 100 such that the display of the first terminal 100 faces theuser may be determined based on whether information obtained via amotion recognition for recognizing a user's motion of facing the displayof the first terminal 100 is included in the first sensor information.

According to another exemplary embodiment, the first terminal 100 maymaintain or terminate a communication established between the firstterminal 100 and the second terminal 300 based on the operationperformed in the operation S530. For example, if a distance between thefirst terminal 100 and the second terminal 300 greater than a criticalvalue is maintained for a set period of time, a communication betweenthe first terminal 100 and the second terminal 300 may be maintained orterminated based on the second state. If the second state indicates thata user possesses or wears the second terminal 300, the first terminal100 may maintain a communication to the second terminal 300. However, ifthe second state indicates that a user is not possessing or wearing thesecond terminal 300, the first terminal 100 may terminate acommunication to the second terminal 300.

The second state indicating whether the user possesses or wears thesecond terminal 300 may be determined by using various methods accordingto various exemplary embodiments. For example, if biometric informationregarding the user is obtained via sensors for obtaining biometricinformation of the user, such as a heart rate sensor, a fingerprintsensor, an iris sensor, a brain wave sensor, and a temperature sensorincluded in the second terminal 300, the second terminal 300 maydetermine that the user has the second terminal 300 on or is wearing thesecond terminal 300. In other words, if heart rate information,fingerprint information, iris information, brain wave information, orbody temperature information of the user is obtained via the sensor 310,the second terminal 300 may determine that the user has the secondterminal 300 on or is wearing the second terminal 300. In anotherexample, if a contact of a user is detected via a touch sensor includedin the second terminal 300 as the user holds the second terminal 300,the second terminal 300 may determine that the user has the secondterminal 300 on or is wearing the second terminal 300. However, one ormore exemplary embodiments are not limited thereto.

In another example, the first terminal 100 may control a volume ofsounds output from the speaker 163 or an intensity of vibrationgenerated by the vibration motor 164 based on a distance between thefirst terminal 100 and the second terminal 300 in the operation S530.For example, the volume output from the speaker 163 may be increased asthe distance between the first terminal 100 and the second terminal 300increases. In detail, the second terminal 300 may be a wearable device,such as a smart watch, whereas the first terminal 100 may be a devicecapable of playing back audio contents, such as a TV. If a user wearsthe second terminal 300 and moves away from the stationary firstterminal 100 while the first terminal 100 is playing back audiocontents, the first terminal 100 may increase the volume of the audiocontent as the distance between the first terminal 100 and the secondterminal 300 increases. In another example, the first terminal 100 maybe a portable device, such as a smart phone, whereas the second terminal300 may be a wearable device, such as a smart watch. The second stateregarding the second terminal 300 worn by a user indicates that thesecond terminal 300 is not moving and the first state regarding thefirst terminal 100 indicates that the first terminal 100 is moving, thesecond terminal 300 may generate vibration by using the vibration motor364 to notify the user of a possible loss of the first terminal 100. Thesecond terminal 300 may increase intensity of vibration as a distancebetween the first terminal 100 and the second terminal 300 increases.However, one or more exemplary embodiments are not limited thereto.

According to another exemplary embodiment, in the operation S530, thefirst terminal 100 may perform an operation determined based on thedistance between the first terminal 100 and the second terminal 300 andthe first state. For example, when the distance between the firstterminal 100 and the second terminal 300 is greater than or equal to acritical value and the first state indicates that a shock is applied tothe first terminal 100, the first terminal 100 may determine that thefirst terminal 100 is dropped on the ground. In detail, a state of thefirst terminal 100 may be determined via shock detecting sensors of thefirst terminal 100, such as an acceleration sensor, a pressure sensor,and a piezo sensor. Since methods for determining a state of the firstterminal 100 to which shock is applied are obvious to one of ordinaryskill in the art, detailed descriptions thereof will be omitted.

When the first terminal 100 is determined to be dropped on the ground,the first terminal 100 may transmit a notification message notifying theuser that the first terminal 100 is dropped on the ground to the secondterminal 300.

FIG. 6 is a timing diagram showing operations of the first terminal 100and the second terminal 300 according to an exemplary embodiment.

First, the first terminal 100 and the second terminal 300 may establisha short-distance wireless communication therebetween (operation S600).The short-distance wireless communication refers to a communicationmethod of transmitting or receiving data within a designated distance.For example, the short-distance wireless communication may includeBluetooth™, infrared data association (IrDA), near field communication(NFC), or ZigBee.

The first terminal 100 may obtain first sensor information by using thesensor 110 (operation S610). The second terminal 300 may obtain secondsensor information by using the sensor 310 (operation S615). The firstterminal 100 may determine a first state based on the obtained firstsensor information (operation S620).

The second terminal 300 may transmit the second sensor informationobtained in the operation S615 to the first terminal 100 (operationS630). The second terminal 300 may transmit obtained second sensorinformation to the first terminal 100 as the second sensor informationis obtained in real-time in the operation S615. Alternatively, thesecond terminal 300 may compress accumulated second sensor informationand transmit the compressed second sensor information to the firstterminal 100 cyclically.

The first terminal 100 may determine a second state based on the secondsensor information received from the second terminal 300 (operationS640).

The first terminal 100 may determine a distance between the firstterminal 100 and the second terminal 300 (operation S650)

Next, the first terminal 100 may perform an operation determined basedon at least one of the distance between the first terminal 100 and thesecond terminal 300, information regarding the first state, andinformation regarding the second state (operation S660).

FIG. 7 is a timing diagram showing operations of the first terminal 100and the second terminal 300 according to another exemplary embodiment.

First, the first terminal 100 and the second terminal 300 may establisha short-distance wireless communication therebetween (operation S700).

The first terminal 100 may obtain first sensor information by using thesensor 110 (operation S710). The second terminal 300 may obtain secondsensor information by using the sensor 310 (operation S715). The firstterminal 100 may determine a first state based on the obtained firstsensor information (operation S720). The second terminal 300 maydetermine a second state based on the obtained second sensor information(operation S725).

Next, the second terminal 300 may transmit information regarding thesecond state determined in the operation S725 to the first terminal 100(operation S730). The second terminal 300 may periodically determine thesecond state and periodically transmit information regarding thedetermined second state to the first terminal 100. According to anotherexemplary embodiment, in the operation S730, the second terminal 300 maytransmit information regarding the second state and the second sensorinformation to the first terminal 100 together. The first terminal 100may update the second state based on the information regarding thesecond state and the second sensor information received from the secondterminal 300.

The first terminal 100 may determine a distance between the firstterminal 100 and the second terminal 300 (operation S740). The firstterminal 100 may determine the distance between the first terminal 100and the second terminal 300 by using various methods according tovarious exemplary embodiments. For example, the first terminal 100 maydetermine the distance between the first terminal 100 and the secondterminal 300 based on an RSSI of a wireless frequency signal used for ashort-distance wireless communication with the second terminal 300.However, one or more exemplary embodiments are not limited thereto. Thefirst terminal 100 may perform an operation determined based on at leastone of the distance between the first terminal 100 and the secondterminal 300, information regarding the first state, and informationregarding the second state (operation S750).

FIG. 8 is a timing diagram showing operations of the first terminal 100and the second terminal 300 according to another exemplary embodiment.

The first terminal 100 may obtain first sensor information by using thesensor 110 (operation S810). Similarly, the second terminal 300 mayobtain second sensor information by using the sensor 310 (operationS815).

The first terminal 100 may transmit the obtained first sensorinformation to a cloud server 800 (S820), and the second terminal 300may transmit the obtained second sensor information to the cloud server800 (S830). The cloud server 800 may determine a first state and asecond state based on the sensor information received from the firstterminal 100 and the second terminal 300 (operation S840).

Furthermore, when a short-distance wireless communication is establishedbetween the first terminal 100 and the second terminal 300 (operationS850), the first terminal 100 may determine a distance between the firstterminal 100 and the second terminal 300 (operation S860). Furthermore,the first terminal 100 may receive the first state and the second statefrom the cloud server 800 (operation S870).

Next, the first terminal 100 may perform an operation determined basedon at least one of the distance determined in the operation S860 and thefirst state and the second state received in the operation S870(operation S880).

The first terminal 100 and the second terminal 300 may establish acommunication using various methods according to various exemplaryembodiments. For example, as shown in FIG. 9, the first terminal 100 andthe second terminal 300 may transmit and receive data to and from eachother via a direct communication without an access point (AP). Forexample, the first terminal 100 and the second terminal 300 may transmitand receive data to and from each other via communication methodsincluding an Ad-hoc method from among Wi-Fi communication methods,Bluetooth™, or ZigBee.

Furthermore, as shown in FIG. 10, the first terminal 100 and the secondterminal 300 may transmit and receive data to and from each other via agateway 1000. For example, the first terminal 100 and the secondterminal 300 may transmit and receive data to and from each other viainfrastructure method from among Wi-Fi communication methods, a homenetwork formed by using a gateway, or a local area network (LAN). Thegateway 1000 may function as an AP.

Furthermore, as shown in FIG. 11, the first terminal 100 and the secondterminal 300 may communicate with a cloud server 1100 via a wired orwireless connection. The first terminal 100 and the second terminal 300may transmit sensor information to the cloud server 1100 and receiveinformation regarding a first state and a second state determined basedon the sensor information from the cloud server 1100.

FIGS. 12 through 14 are diagrams for describing operations of the firstterminal 100 and the second terminal 300 according to an exemplaryembodiment.

As shown in FIG. 12, the first terminal 100 may be a smart phone thatmay be carried by a user, and the second terminal 300 may be a wearabledevice that may be worn by the user. As shown in FIG. 12, in the casewhere a critical value of a distance 1200 between the first terminal 100and the second terminal 300 is 2 m, the first terminal 100 or the secondterminal 300 may determine whether to perform an operation based on afirst state, a second state, and the distance 1200 when the distance1200 is 2 m.

When a short-distance wireless communication is established between asmart phone and a wearable device, if a user moves without carrying thesmart phone, a distance between the smart phone and the wearable deviceincreases. In this case, the user is likely not using the smart phone.Therefore, as shown in FIG. 13, if a distance between the first terminal100 and the second terminal 300 is greater than a critical value (e.g.,2 m), the smart phone, which is the first terminal 100, is not moving,and the wearable device, which is the second terminal 300, is moved froman original location 1300, the first terminal 100 may switch to astandby mode to reduce power consumption. In this case, a first stateindicating a state of the first terminal 100 may indicate that no motionis detected. Furthermore, a second state indicating a state of thesecond terminal 300 may indicate that a motion is detected. The standbymode may refer to a mode in which a display, a sensor, and acommunicator are deactivated.

Furthermore, since a wearable device is worn on a body part of a user, astate in which the wearable device is not moving may refer to a state inwhich the user is not moving. Therefore, a state in which a smart phonemoves while a wearable device is not moving may refer to a state thatthe smart phone is being moved by a person other than the user.

If the first state indicates that a motion is detected and the secondstate indicates that no motion is detected, the first and second statesmay indicate that the first terminal 100 is moved from an originallocation 1400, as shown in FIG. 14. Therefore, when a distance betweenthe first terminal 100 and the second terminal 300 is greater than acritical value (e.g., 2 m), if the first state indicates that a motionis detected and the second state indicates that no motion is detected,an anti-theft alarm message 1410 may be output to the second terminal300. The anti-theft alarm message 1410 may be a message transmitted bythe first terminal 100 or a message generated by the second terminal300.

Related to the exemplary embodiments shown in FIGS. 12 through 14, FIG.15A is a diagram for describing an operation determined based on a firststate and a second state. When a distance between the first terminal 100and the second terminal 300 is greater than a critical value, the firstterminal 100 and the second terminal 300 may operate as shown in FIG.15A.

The first state may indicate that a motion of the first terminal 100 isdetected, whereas the first state may indicate that a motion of thesecond terminal 300 is detected. In this case, an alarm message may bedisplayed at least one of the two terminals (the first terminal 100 andthe second terminal 300). Furthermore, if states of the first terminal100 and the second terminal 300 are identical to those shown in FIG. 13,the first state may indicate that no motion of the first terminal 100 isdetected and the second state may indicate that a motion of the secondterminal 300 is detected. In this case, the first terminal 100 mayswitch an operation mode of the first terminal 100 to a standby mode.Furthermore, if states of the first terminal 100 and the second terminal300 are identical to those shown in FIG. 14, the first state mayindicate that a motion of the first terminal 100 is detected and thesecond state may indicate that no motion of the second terminal 300 isdetected. In this case, an alarm message may be displayed at the secondterminal 300. If both the first state and the second state indicate nomotion is detected, the change of a distance between the first terminal100 and the second terminal 300 without motions of the first terminal100 and the second terminal 300 may indicate that at least one of thefirst state, the second state, and the distance between the firstterminal 100 and the second terminal 300 is erroneous. Therefore, inthis case, the first terminal 100 or the second terminal 300 maydetermine at least one of the first state, the second state, and thedistance between the first terminal 100 and the second terminal 300again.

FIG. 15B is a diagram for describing an operation determined based on afirst state and a second state. If a distance between the first terminal100 and the second terminal 300 is greater than a critical value, thefirst terminal 100 and the second terminal 300 may operate as shown inFIG. 15B.

If the first terminal 100 is stolen by another person, the distancebetween the first terminal 100 and the second terminal 300 may begreater than the critical value, a motion of the first terminal 100 maybe detected, and no motion of the second terminal 300 may be detected.Therefore, in this case, the first terminal 100 may be configured totransmit a loss/theft notification message to the second terminal 300.The second terminal 300, which received the loss/theft notificationmessage, may display the received loss/theft notification message.Furthermore, the first terminal 100 may execute a data protection modefor protecting data stored therein.

When a user moves and the first terminal 100 was left behind, thedistance between the first terminal 100 and the second terminal 300 maybe greater than the critical value, no motion of the first terminal 100may be detected, and a motion of the second terminal 300 may bedetected. Therefore, in this case, the first terminal 100 may beconfigured to transmit a standby mode notification message indicatingthat the first terminal 100 is in the standby mode to the secondterminal 300. The second terminal 300, which received the standby modenotification message, may display the received standby mode notificationmessage. Furthermore, the first terminal 100 may set up the standby modefor reducing power consumption.

Furthermore, if the first terminal 100 is stolen, the distance betweenthe first terminal 100 and the second terminal 300 may be greater thanthe critical value, a motion of the first terminal 100 may be detected,and a motion of the second terminal 300 may also be detected. Therefore,in this case, the first terminal 100 may be configured to transmit aloss/theft notification message to the second terminal 300. The secondterminal 300, which received the loss/theft notification message, maydisplay the received loss/theft notification message. Furthermore, thefirst terminal 100 may execute a data protection mode for protectingdata stored therein.

If the distance between the first terminal 100 and the second terminal300 is greater than the critical value, no motion of the first terminal100 is detected, and no motion of the second terminal 300 is detected,at least one of the first state, the second state, and the distancebetween the first terminal 100 and the second terminal 300 is erroneous.Therefore, in this case, the first terminal 100 or the second terminal300 may determine at least one of the first state, the second state, andthe distance between the first terminal 100 and the second terminal 300again.

FIG. 16 is a flowchart for describing a process in which the firstterminal 100 performs an operation based on a first state and a secondstate, according to an exemplary embodiment.

The first terminal 100 may determine the first state indicating a stateof the first terminal 100 (operation S1610) and determine the secondstate indicating a state of the second terminal 300 (operation S1620).The first state may include information regarding a motion of the firstterminal 100. Furthermore, the second state may include informationregarding a motion of the second terminal 300. Information regarding amotion of a terminal may include information regarding a direction, aspeed, and a pattern of the motion of the terminal.

Next, the first terminal 100 may determine whether a distance betweenthe first terminal 100 and the second terminal 300 is greater than orequal to a critical value (operation S1630). If the distance between thefirst terminal 100 and the second terminal 300 is less than the criticalvalue, the first terminal 100 may update the first state and the secondstate again (operations S1610 and S1620). If the distance between thefirst terminal 100 and the second terminal 300 is less than the criticalvalue, the first state and the second state may be periodically updated.

If the distance between the first terminal 100 and the second terminal300 is greater than or equal to the critical value (operation S1630),the first terminal 100 may determine whether the first terminal 100 ismoving based on the first state (operation S1640).

In a state that a motion of the first terminal 100 is being detected,the first terminal 100 may determine whether the second terminal 300 ismoving based on the second state (operation S1650). If the second stateindicates that a motion of the second terminal 300 is being detected,the first terminal 100 may display an alarm message (operation S1660).Furthermore, the first terminal 100 may transmit the alarm message tothe second terminal 300 (operation S1665). However, if the second stateindicates that no motion of the second terminal 300 is detected, thefirst terminal 100 may only transmit an alarm message to the secondterminal 300 (operation S1670).

In a state that no motion of the first terminal 100 is being detected,the first terminal 100 may determine whether the second terminal 300 ismoving based on the second state (operation S1655). If the second stateindicates that a motion of the second terminal 300 is being detected,the first terminal 100 may switch an operation mode of the firstterminal 100 to a standby mode (operation S1680). However, if the secondstate indicates that no motion of the second terminal 300 is detected,the first terminal 100 may perform the process from the operation S1610.

According to an exemplary embodiment, detection of a motion of the firstterminal 100 or the second terminal 300 in the operations S1640, S1650,and S1655 may mean that a designated motion of a user possessing thefirst terminal 100 or the second terminal 300 is detected. For example,if information regarding a direction, a speed, and a pattern of a motionof the first terminal 100 included in the first state (determined basedon the first sensor information) is similar to a direction, a speed, anda pattern corresponding to the case in which a user possessing the firstterminal 100 is walking, the first terminal 100 may determine that amotion of the first terminal 100 is detected in the operation S1640. Inthe same regard, in the operations S1650 and S1655, if informationincluded in the second state indicates a designated motion of a userpossessing the second terminal 300, the first terminal 100 may determinethat a motion of the second terminal 300 is detected.

FIG. 17 is a flowchart for describing a process in which the firstterminal 100 performs an operation based on a wearing state of thesecond terminal 300, according to another exemplary embodiment.

First, the first terminal 100 may establish a communication with thesecond terminal 300 (operation S1710). Next, the first terminal 100 maydetermine a second state based on second sensor information orinformation regarding the second state received from the second terminal300 (operation S1720).

Next, the first terminal 100 may determine whether a distance betweenthe first terminal 100 and the second terminal 300 is greater than orequal to a critical value (operation S1730). According to an exemplaryembodiment, the first terminal 100 may determine whether the distancebetween the first terminal 100 and the second terminal 300 greater thanthe critical value is maintained for a set period of time. If thedistance between the first terminal 100 and the second terminal 300 isless than the critical value, the first terminal 100 may update thesecond state by re-performing the operation S1720. If the distancebetween the first terminal 100 and the second terminal 300 is neitherequal to nor greater than the critical value, the first terminal 100 mayperiodically update the second state by re-performing the operationS1720 after a designated time period elapses.

If the distance between the first terminal 100 and the second terminal300 is greater than or equal to the critical value, the first terminal100 may determine whether the second state indicates that the user iswearing the second terminal 300, based on the second state. If thesecond state indicates that the user is wearing the second terminal 300,the first terminal 100 may update the second state by re-performing theoperation S1720. The first terminal 100 may periodically update thesecond state by re-performing the operation S1720 after a designatedtime period has elapsed. Alternatively, if the second state indicatesthat the user is not wearing the second terminal 300, the first terminal100 may terminate a communication to the second terminal 300 (operationS1750).

FIG. 18 is a flowchart for describing a process of performing anoperation determined based on feedback information regarding anoperation performed by the first terminal 100, according to an exemplaryembodiment.

The first terminal 100 may receive feedback information regarding theoperation performed by the first terminal 100 in the operation S530 ofFIG. 5 (operation S1810). The first terminal 100 may receive feedbackinformation in various ways according to various exemplary embodiments.The first terminal 100 may receive feedback information by using atleast one method including receiving a direct response from a user,receiving an indirect response from a user, and recognizing asurrounding environment.

The method of receiving a direct response from a user may include amethod of receiving an input for selecting at least one of a pluralityof menus included in a user interface from the user. Alternatively, thefirst terminal 100 may receive a voice command of a user via themicrophone 162. Furthermore, the first terminal 100 may receive agesture command of a user as a feedback input via an accelerationsensor, a gyro sensor, or the camera 150.

The method of receiving an indirect response from a user may include amethod of obtaining feedback information based on biometric signals byusing a sensor included in the first terminal 100. For example, afterthe first terminal 100 or the second terminal 300 outputs an alarmmessage, biometric signals including at least one of a heart rate, ablood pressure, a muscle movement, and a brain wave may be obtained byusing at least one of a heart rate sensor, a blood pressure sensor, amuscle sensor, and a brain wave sensor.

In the method of recognizing a surrounding environment, as non-limitingexamples, ambient noises may be recognized by using the microphone 162,ambient luminance may be recognized by using a luminance sensor of thesensor 110, or information regarding a location of the first terminal100 may be obtained by using the GPS device 140.

Next, the first terminal 100 may perform an operation determined basedon obtained feedback information (operation S1820). If the firstterminal 100 or the second terminal 300 outputted an alarm message inthe operation S530, the operation determined based on the feedbackinformation according to an exemplary embodiment may be an operation foroutputting an additional alarm message to the first terminal 100 or thesecond terminal 300. In this case, the first terminal 100 may output anadditional alarm message based on the feedback information obtained inthe operation S1810.

For example, if a biometric signal obtained in the operation S1810changes, the first terminal 100 may determine that the user is nervousand may reduce the intensity of a vibration or volume of a sound foroutputting an additional alarm message. In another example, if an alarmmessage is output to the second terminal 300, an additional alarmmessage may be output to a terminal other than the second terminal 300based on a menu selecting input or voice of a user received in theoperation S1810. In other words, if an alarm message is output to awearable device, an alarm message may be output using a speaker or adisplay arranged in a vehicle. For example, even if the second terminal300 outputs an alarm message regarding loss of the first terminal 100 asa user loses the first terminal 100, the user may not check the alarmmessage. Next, if the user enters into a vehicle, a short-distancewireless communication may be established between the second terminal300 and the vehicle, and an alarm message regarding the loss may beadditionally output via a speaker of the vehicle. However, one or moreexemplary embodiments are not limited thereto.

Furthermore, the first terminal 100 may change a period for outputtingadditional alarm messages based on feedback information. Furthermore,the first terminal 100 may change a form or a content of an additionalalarm message. For example, if an alarm message is a theft notificationmessage, the additional alarm message may be a message indicatinginformation regarding a location of the first terminal 100 or the secondterminal 300. In another example, feedback information may includeinformation regarding ambient noises. If levels of the ambient noisesare high, the volume of an alarm message may be increased (in the caseof outputting the alarm message as a sound), the intensity of avibration may be increased (in the case of outputting the alarm messageas a vibration), or the alarm message may be output a plurality ofnumber of times at short intervals. However, one or more exemplaryembodiments are not limited thereto.

FIG. 19 is a flowchart showing a process in which the first terminal 100performs an advanced synchronization according to an exemplaryembodiment.

First, the first terminal 100 may determine whether a user is holdingthe first terminal 100 (operation S1910). Various methods may be used todetermine whether the user is holding the first terminal 100, accordingto various exemplary embodiments. FIG. 20 is a schematic diagram showingthe first terminal 100 performing an advanced synchronization accordingto the exemplary embodiment shown in FIG. 19. Referring to FIG. 20, thefirst terminal 100 may include a camera 2010 arranged on a same surfaceas a display 2000. If the user holds the first terminal 100, such thatthe display 2000 faces toward the face of the user, the first terminal100 may photograph the face of the user by using the camera 2010. If animage captured by the camera 2010 includes the face of the user, thefirst terminal 100 may determine that the user is holding the firstterminal 100. The first terminal 100 may perform image recognition withrespect to the captured image. Alternatively, the first terminal 100 mayinclude a touch sensor 2020. If the user contacts the touch sensor 2020by holding the first terminal 100, the first terminal 100 may receive atouch input via the touch sensor 2020. The first terminal 100 maydetermine whether the user is holding the first terminal 100 based on areceived touch input.

If the user is determined to be holding the first terminal 100(operation S1920-Y), the first terminal 100 may update a first state anda second state (operation S1930). The first terminal 100 may receivesecond sensor information from the second terminal 300 as shown in FIG.6, receive information regarding the second state from the secondterminal 300 as shown in FIG. 7, or receive information regarding thefirst state and the second state from the cloud server 800 as shown inFIG. 8. However, one or more exemplary embodiments are not limitedthereto.

The user may continue to update the first state and the second statewhile the user is determined to be holding the first terminal 100(S1930-S1950).

FIG. 21 is a flowchart showing a process of performing an advancedsynchronization, according to another exemplary embodiment.

First, the first terminal 100 may establish a short-distance wirelesscommunication with the second terminal 300 (operation S2110). Next, thefirst terminal 100 may determine a distance between the first terminal100 and the second terminal 300 that are connected to each other via theshort-distance wireless communication (operation S2120). The distancebetween the first terminal 100 and the second terminal 300 may bedetermined by using various methods according to various exemplaryembodiments. Next, if a determined distance is greater than a criticalvalue (operation S2130-N), the first terminal 100 may monitor thedistance between the first terminal 100 and the second terminal 300 byperforming the operation S2120 periodically.

If the distance determined in the operation S2120 is less than or equalto the critical value (the operation S2130-Y), the first terminal 100may update the first state and the second state (operation S2140). Forexample, referring to FIG. 22, if a user 2200 wearing the secondterminal 300, which is a wearable device, approaches the first terminal100 and holds the first terminal 100, the first terminal 100 and thesecond terminal 300 are near each other. In this case, the firstterminal 100 may update the first state and the second state for anadvanced synchronization. In an operation S2140, the first terminal 100may update the first state and the second state via at least one of theprocesses shown in FIGS. 6 through 8. In other words, the first terminal100 may obtain information regarding the first state and informationregarding the second state and determine the first state and the secondstate based on the obtained information. After a designated time periodelapses after the operation S2140, the first terminal 100 may determinea distance between the first terminal 100 and the second terminal 300again. If the determined distance is less than or equal to the criticalvalue (operation S2150-Y), the first terminal 100 may perform theoperation S2140, thereby periodically updating the first state and thesecond state while the first terminal 100 and the second terminal 300are near each other. However, if the determined distance is greater thanthe critical value (the operation S2150-N), the first terminal 100 mayterminate the short-distance wireless communication with the secondterminal 300 (operation S2160).

To prevent the short-distance wireless communication from beingterminated if the user temporarily puts down the first terminal 100, thecritical value of the operation S2130 may be different from the criticalvalue of the operation S2150. In other words, the critical value of theoperation S2150 may be greater than the critical value of the operationS2130. For example, in the operation S2130, the critical value may beabout 50 cm to recognize a state that the user possesses both the firstterminal 100 and the second terminal 300. Furthermore, in the operationS2150, the critical value may be about 10 m to maintain theshort-distance wireless communication when the user wearing the secondterminal 300 is near the first terminal 100.

FIG. 23 is a flowchart showing a process of displaying a notificationmessage on the second terminal 300, according to an exemplaryembodiment. According to an exemplary embodiment, if the first terminal100 is stolen by another person, a notification message may be displayedat the second terminal 300 to prevent important information of a userfrom being exposed to the another person from the first terminal 100.Furthermore, FIGS. 24 through 26 are diagrams for describing examples ofdisplaying notification messages at the second terminal 300 according tothe exemplary embodiment shown in FIG. 23.

Referring to FIG. 23, in an operation S2310, the first terminal 100 mayestablish a short-distance wireless communication with the secondterminal 300. Next, based on the short-distance wireless communicationestablished in the operation S2310, the first terminal 100 may determinea first state, a second state, and a distance between the first terminal100 and the second terminal 300 (operation S2320).

Next, in an operation S2330, the first terminal 100 may determinewhether the distance between the first terminal 100 and the secondterminal 300 is greater than or equal to a critical value. The firstterminal 100 may determine whether the first terminal 100 is stolenbased on the first state and the second state in the operation S2330.For example, as the conditions as shown in FIG. 14 are given, the secondstate may indicate that a user is not moving, whereas the first statemay indicate that the user is walking. In this case, if the distancebetween the first terminal 100 and the second terminal 300 is greaterthan or equal to the critical value, the first terminal 100 maydetermine that the first terminal 100 is stolen. If the distance betweenthe first terminal 100 and the second terminal 300 is less than or equalto the critical value, the first terminal 100 may perform the operationS2320 again.

FIG. 24 shows an exemplary embodiment in the case where the firstterminal 100 is a mobile phone and the second terminal 300 is a wearabledevice that may be worn on a wrist of a user 2410. If the first terminal100 is stolen by another person 2420, a distance 2400 between the firstterminal 100 and the second terminal 300 increases. Furthermore, if theanother person 2420 moves while holding the first terminal 100, motionsthat may be obtained via the first terminal 100 may show a pattern ofmotions that is detected as a person moves while holding the firstterminal 100. If the distance 2400 is greater than or equal to a pre-setcritical value and the first state and the second state indicate thatthe first terminal 100 and the second terminal 300 are being moved indifferent directions or the first terminal 100 is being moved while thesecond terminal 300 is not being moved, the first terminal 100 may bestolen by the another person 2420.

In the operation S2330, if the distance 2400 is greater than or equal tothe critical value (or the first terminal 100 is determined to bestolen), the first terminal 100 may determine whether an input that isdesignated as an input corresponding to a major function is received(operation S2340). If the designated input is received (S2340-Y), thefirst terminal 100 may transmit a notification message to the secondterminal 300 (S2350). The notification message may include informationregarding an input received by the first terminal 100. For example, if areceived input is an input for retrieving picture data, the firstterminal 100 may transmit a message “there was an attempt to retrievepictures at a first terminal” to the second terminal 300. A user mayrecognize that there was an attempt to retrieve personal informationbased on the message displayed at the second terminal 300.

The designated input stated above in relation to the operation S2340 mayvary according to various exemplary embodiments. For example, referringto FIG. 25, the another person 2420 may input a touch pattern 2500 tothe first terminal 100, which is stolen by the another person 2420, tounlock a lock screen. If the first terminal 100 is determined to bestolen based on the first state, the second state, and the distancebetween the first terminal 100 and the second terminal 300, the firstterminal 100 may transmit a message 2510, e.g., “a wrong pattern isinput to the mobile phone,” to the second terminal 300. The user 2410may recognize that the another person 2420 attempted to unlock a lockscreen of the first terminal 100 based on the message 2510 displayed atthe second terminal 300.

Methods by which the first terminal 100 transmits the message 2510 tothe second terminal 300 may vary according to various exemplaryembodiments. For example, if a short-distance wireless communication isavailable between the first terminal 100 and the second terminal 300,the first terminal 100 may transmit the message 2510 to the secondterminal 300 via the short-distance wireless communication.Alternatively, the first terminal 100 may transmit the message 2510 tothe second terminal 300 via a separate network, such as a mobilecommunication network or the internet. However, one or more exemplaryembodiments are not limited thereto.

Further, referring to FIG. 26, the designated input may be an input foraccessing personal information regarding the user 2410 via the firstterminal 100. Personal information regarding the user 2410 may includeimages, messages, financial information, and identification informationstored in a terminal. However, one or more exemplary embodiments are notlimited thereto. As shown in FIG. 26, if the another person 2420 selectsan application execution icon for executing a finance-relatedapplication (in the case where the first terminal 100 is determined tobe stolen), the first terminal 100 may transmit a message 2610, e.g.,“there was an attempt to access personal information,” to the secondterminal 300. Methods by which the first terminal 100 transmits themessage 2610 to the second terminal 300 may vary according to variousexemplary embodiments.

FIG. 27 is a flowchart showing a process in which the first terminal 100transmits a notification message to the second terminal 300, accordingto an exemplary embodiment. If an operation determined based on a firststate, a second state, and a distance between the first terminal 100 andthe second terminal 300 is an operation for transmitting a notificationmessage, the first terminal 100 may transmit a notification message to aterminal that is being currently used by a user.

If an operation determined in the operation S530 (FIG. 5) based on afirst state, a second state, and a distance between the first terminal100 and the second terminal 300 is an operation for transmitting anotification message, the first terminal 100 may search for and select asecond terminal that is being currently used by a user in an operationS2710. Referring to FIG. 28, the first terminal 100 may select (that is,search for) a terminal that is being currently used by a user 2810 fromamong terminals 300-1, 300-2, and 300-3. The terminals 300-1, 300-2, and300-3 include terminals that the first terminal 100 may directly orindirectly communicate with. For example, the terminals 300-1, 300-2,and 300-3 may include terminals connected to the first terminal 100 viaa short-distance wireless communication or terminals connected to anetwork to which the first terminal 100 is connected to. However, one ormore exemplary embodiments are not limited thereto. Furthermore, theterminals 300-1, 300-2, and 300-3 may include the second terminal 300.

According to an exemplary embodiment, in the operation S2710, the firstterminal 100 may transmit, to the terminals 300-1, 300-2, and 300-3, asearch signal indicating information that a device being currently usedby the user 2810 is being searched for. When the search signal isreceived, the terminal 300-1 being currently used by the user 2810 maytransmit a response signal indicating that the user 2810 is currentlyusing the terminal 300-1 to the first terminal 100. Alternatively,according to another exemplary embodiment, in the operation S2710, thefirst terminal 100 may access the terminals 300-1, 300-2, and 300-3without transmitting a search signal. The first terminal 100 may analyzethe terminals 300-1, 300-2, and 300-3 and search for the terminal 300-1being used by the user 2810 from among the terminals 300-1, 300-2, and300-3. For example, if a universal plug and play (UPnP) service may bedesignated by a UPnP protocol, and a terminal registered to the UPnPservice may be considered as a terminal being currently used by a user.If a terminal being currently used by a user is not found, the firstterminal 100 may search for a shared network that the first terminal 100may access and search for a terminal being currently used by the user byusing the shared network. Alternatively, the first terminal 100 maysearch for a terminal being currently used by the user by scanningterminals included in a terminal list database included in the firstterminal 100.

Next, the first terminal 100 may transmit a notification message to theterminal selected in the operation S2710 (operation S2720). According toan exemplary embodiment, if no response message is received from aterminal to which a notification message is transmitted within adesignated time period after the notification message is transmitted,the first terminal 100 may select another terminal and re-transmit anotification message to the newly selected terminal.

FIG. 29 is a flowchart showing a process in which the first terminal 100operates according to another exemplary embodiment. Furthermore, FIGS.30 through 33 are diagrams showing methods of using the first terminal100 and the first terminal 300 for lost child prevention based on theexemplary embodiment shown in FIG. 29. However, the exemplaryembodiments shown in FIGS. 30 through 33 are merely non-limitingexamples.

In an operation S2910, the first terminal 100 may determine a firststate indicating a state of the first terminal 100. For example, thefirst state may include a motion of the first terminal 100, a directionin which the first terminal 100 is moving, or a pattern of motions ofthe first terminal 100. The first state may correspond to first sensorinformation. For example, the first terminal 100 may determine adirection in which the first terminal 100 is moving by using the GPSdevice 140 of the first terminal 100 or a geomagnetic sensor of thesensor 110. In the case of using the GPS device 140, the first terminal100 may periodically obtain a location of the first terminal 100.Alternatively, the first terminal 100 may obtain a location of the firstterminal 100 when an event occurs. The event may refer to an operationor an event occurring with respect to the first terminal 100. Forexample, if a motion of the first terminal 100 is detected by using anacceleration sensor, the first terminal 100 may obtain a location of thefirst terminal 100. Next, based on a change of location of the firstterminal 100, the first terminal 100 may determine a direction in whichthe first terminal 100 is moving. Alternatively, in the case of usingthe geomagnetic sensor, the first terminal 100 may periodically obtainan azimuth angle of the first terminal 100. Alternatively, the firstterminal 100 may obtain an azimuth angle of the first terminal 100 whenan event occurs. The azimuth angle may be an angle between a baseline ofthe N pole of the Earth's magnetic field and a direction that the firstterminal 100 faces. Next, based on a change in the azimuth angle of thefirst terminal 100, the first terminal 100 may determine the directionin which the first terminal 100 is moving.

Furthermore, in an operation S2920, the second terminal 300 maydetermine a second state indicating a state of the second terminal 300.For example, the second state may include a motion of the secondterminal 300, a direction in which the second terminal 300 is moving, ora pattern of motions of the second terminal 300. The second state maycorrespond to second sensor information.

For example, the second terminal 300 may determine a direction in whichthe second terminal 300 is moving by using the GPS device 340 of thesecond terminal 300 or a geomagnetic sensor of the sensor 310. A methodby which the second terminal 300 determine a moving direction by usingthe GPS device 340 or the geomagnetic sensor is similar to the methoddescribed above with reference to the first terminal 100.

In an operation S2930, the first terminal 100 may determine whether adistance between the first terminal 100 and the second terminal 300 isgreater than or equal to a critical value. FIGS. 30 through 33 arediagrams showing an exemplary embodiment corresponding to the case inwhich a first user 3010 possesses the first terminal 100, which is amobile phone, and a second user 3030 is wearing the second terminal 300,which is a wearable device. The first terminal 100 may determine adistance 3020 between the first terminal 100 and the second terminal300. The first terminal 100 may determine whether the distance 3020 isless than a critical value 3025 (e.g., 5 m). The critical value 3025 mayalso be set based on a user-input value input to the first terminal 100.If the distance 3020 is less than the critical value 3025 (S2930-N), thefirst terminal 100 may not perform any particular operation and mayagain perform the operation S2910 after an arbitrary time period haselapsed. In other words, if the second user 3030 is within a criticaldistance from the first user 3010, the first terminal 100 may notperform any additional operation other than an operation forperiodically monitoring a first state and a second state.

If the distance 3020 between the first terminal 100 and the secondterminal 300 is greater than or equal to the critical value 3025(S2930-Y), the first terminal 100 may determine in an operation S2940whether the second state indicates that a motion of the second terminal300 is detected. If no motion of the second terminal 300 is detected,the second user 3030 is not moving (S2940-N), and thus the firstterminal 100 may not perform any particular operation and may againperform the operation S2910 after an arbitrary time period has elapsed.However, if the second state indicates that a motion of the secondterminal 300 is detected (S2940-Y), the first terminal 100 may determinein an operation S2950 whether the first state indicates that a motion ofthe first terminal 100 is detected. Detection of a motion of a terminalmay mean that first sensor information or second sensor information mayinclude information regarding a pattern in which a terminal moves.

If a motion of the second terminal 300 is detected and no motion of thefirst terminal 100 is detected (S2950-N), the first terminal 100 maydisplay a notification message (operation S2960). The notificationmessage may be a message, which instructs the first user 3010 to check alocation of the child 3030. Referring to FIG. 31, when the first user3010 is not moving and the second user 3030 moves from a previouslocation 3100 in a direction 3102, a distance between the two terminalsmay be greater than or equal to the critical value 3025. In this case,the second user 3030 may move away from the first user 3010 without thefirst user 3010 realizing it, the first terminal 100 may output anotification message for lost child prevention.

If a motion of the first terminal 100 is detected in the operationS2950, the first terminal 100 may determine in an operation S2955whether the first terminal 100 and the second terminal 300 are moving ina same direction. The expression “moving in a same direction” includesthe expression “moving in similar directions.” If the first terminal 100and the second terminal 300 are moving in a same direction (S2955-Y),the first terminal 100 may not perform any particular operation and mayagain perform the operation S2910 after an arbitrary time period haselapsed. Referring to FIG. 32, as the second user 3030 moves from aprevious location 3220 in a direction 3222, a distance from the firstuser 3010 to the second user 3030 is greater than the critical value3025. However, if a direction 3212 in which the first user 3010 from anoriginal location 3210 is identical to the direction 3222 in which thesecond user 3030 is moving, the first user 3010 and the second user 3030are moving in a same direction, and, thus, the first terminal 100 maynot display a lost child prevention message.

If the first terminal 100 and the second terminal 300 are not moving ina same direction in the operation S2955, the first terminal 100 maydisplay a notification message (operation S2960). Referring to FIG. 33,as the second user 3030 moves from an original location 3320 in adirection 3322, a distance from the first user 3010 to the second user3030 is greater than the critical value 3025. Since a direction 3312 inwhich the first user 3010 is moving from an original location 3310 isdifferent from the direction 3322 in which the second user 3030 ismoving from the original location 3320, the first terminal 100 shoulddisplay a notification message for lost child prevention to the firstuser 3010.

FIG. 34 is a flowchart showing a process in which the first terminal 100operates according to another exemplary embodiment, and FIGS. 35 through38 are diagrams showings a method of using the first terminal 100 andthe second terminal 300 for lost child prevention based on ambientluminance, according to the exemplary embodiment shown in FIG. 34. Whenan ambient environment is bright, even if a child with the secondterminal 300 moves away from a parent with the first terminal 100, theparent may easily locate the child. Therefore, a critical value of adistance between the first terminal 100 and the second terminal 300 maybe relatively large during periods of relatively high luminance, such asdaytime. However, when the ambient environment is dark, even if adistance between the parent with the first terminal 100 and the childwith the second terminal 300 is relatively small, the parent may havedifficulty locating the child. Therefore, a critical value of a distancebetween the first terminal 100 and the second terminal 300 may berelatively small during periods of relatively low luminance, such as atnight. In this case, a notification message may be output to the parenteven if the child moves away from the parent for a relatively smalldistance.

In an operation S3410, the first terminal 100 may determine a firststate indicating a state of the first terminal 100. In an operationS3420, the second terminal 300 may determine a second state indicating astate of the second terminal 300.

In an operation S3430, the first terminal 100 may determine a luminancearound the first terminal 100 by using the luminance sensor of thesensor 110. Alternatively or additionally, the second terminal 300 maydetermine a luminance around the second terminal 300 by using theluminance sensor of the sensor 310.

In an operation S3440, the first terminal 100 may determine a criticalvalue of a distance between the first terminal 100 and the secondterminal 300 based on the determined luminance. For example, if theluminance determined by the first terminal 100 is more than 10 lux, thecritical value of the distance between the first terminal 100 and thesecond terminal 300 may be about 5 m. Alternatively, if the luminancedetermined by the first terminal 100 is between 1 lux and 10 lux, thecritical value of the distance between the first terminal 100 and thesecond terminal 300 may be about 4 m. Alternatively, if the luminancedetermined by the first terminal 100 is less than or equal to 1 lux, thecritical value of the distance between the first terminal 100 and thesecond terminal 300 may be about 3 m.

The first terminal 100 may determine the critical value based on atleast one of a luminance around the first terminal 100 and a luminancearound the second terminal 300. For example, the first terminal 100 maydetermine the critical value based on a smaller value between, anaverage of, or a median value of the luminance around the first terminal100 and the luminance around the second terminal 300. In anotherexample, the second terminal 300 may select a smaller value between, anaverage of, or a median value of the luminance around the first terminal100 and the luminance around the second terminal 300 and provide theselected value to the first terminal 100.

In an operation S3450, the first terminal 100 may determine whether thedistance between the first terminal 100 and the second terminal 300 isless than or equal to the determined critical value. FIG. 35 is adiagram showing an exemplary embodiment corresponding to the case inwhich the determined critical value is 3 m, a first user 3510 possessesthe first terminal 100, which is a mobile phone, and a second user 3530is wearing the second terminal 300, which is a wearable device. Thefirst terminal 100 may determine a distance 3520 between the firstterminal 100 and the second terminal 300. The first terminal 100 maydetermine whether the distance 3520 between the first terminal 100 andthe second terminal 300 is less than or equal to a critical value 3525(e.g., 3 m). If the distance 3520 between the first terminal 100 and thesecond terminal 300 is less than the critical value 3525 (S3450-N), thefirst terminal 100 may not perform any particular operation and mayagain perform the operation S3410 after an arbitrary time period haselapsed,

If the distance 3520 between the first terminal 100 and the secondterminal 300 is greater than or equal to the critical value 3525(S3450-Y), the first terminal 100 may determine whether the second stateindicates that a motion of the second terminal 300 is detected. If nomotion of the second terminal 300 is detected (S3460-N), the second user3530 is not moving, and thus the first terminal 100 may not perform anyparticular operation. Furthermore, the first terminal 100 may againperform the operation S3410 after an arbitrary time period has elapsed.However, if a motion of the second terminal 300 is detected (S3460-Y),the first terminal 100 may determine in an operation S3470 whether thefirst state indicates that a motion of the first terminal 100.

If a motion of the second terminal 300 is detected and no motion of thefirst terminal 100 is detected (S3470-N), the first terminal 100 maydisplay a notification message (operation S3480). The notificationmessage may be a message that instructs the first user 3510 to check alocation of the child. Referring to FIG. 36, when the first user 3510 isnot moving and the second user 3530 moves from a previous location 3500in a direction 3602, a distance between the two terminals may be greaterthan or equal to the critical value 3525. In this case, the second user3530 may move away from the first user 3510 without the first user 3510realizing it, and the first terminal 100 may output a notificationmessage for lost child prevention.

If a motion of the first terminal 100 is detected in the operationS3470, the first terminal 100 may determine in an operation S3475whether the first terminal 100 and the second terminal 300 are moving ina same or similar direction. If the first terminal 100 and the secondterminal 300 are moving in a same or similar direction (S3475-Y), thefirst terminal 100 may not perform any particular operation and mayagain perform the operation S3410 after an arbitrary time period haselapsed. Referring to FIG. 37, FIG. 37 shows that, as the second user3530 moved from a previous location 3720 in a direction 3722, a distancefrom the first user 3510 to the second user 3530 is greater than thecritical value 3525. However, if a direction 3712 in which the firstuser 3510 from an original location 3710 is identical or similar to thedirection 3722 in which the second user 3530 is moving, the first user3510 and the second user 3530 are moving in a same direction, and, thus,the first terminal 100 may not display a lost child prevention message.

If the first terminal 100 and the second terminal 300 are not moving ina same direction in the operation S3475, the first terminal 100 maydisplay a notification message (operation S3480). Referring to FIG. 38,FIG. 38 shows that, as the second user 3530 moved from an originallocation 3870 in a direction 3822, a distance from the first user 3510to the second user 3530 is greater than the critical value 3525. Since adirection 3812 in which the first user 3510 is moving from an originallocation 3810 is different from the direction 3822 in which the seconduser 3530 is moving, the first terminal 100 should display anotification message for lost child prevention to the first user 3510.

FIG. 39 is a flowchart showing a process of displaying a notificationmessage on the second terminal 300, according to another exemplaryembodiment. According to an exemplary embodiment, if a user drops thefirst terminal 100, a notification message may be displayed at thesecond terminal 300 possessed or worn by the user. Alternatively, beforethe user drops the first terminal 100, an operation for preparing for acase that a shock is applied to the first terminal 100 (e.g., anoperation for storing backup data of the first terminal 100) may beperformed. FIGS. 40 and 41 are diagrams for describing an example thatthe second terminal 300 displays a notification message according to theexemplary embodiment shown in FIG. 39.

Referring to FIG. 39, in an operation S3910, the first terminal 100 mayestablish a short-distance wireless communication with the secondterminal 300. Next, in an operation S3920, the first terminal 100 maydetermine a distance between the first terminal 100 and the secondterminal 300 based on the established short-distance wirelesscommunication.

Next, in an operation S3930, the first terminal 100 or the secondterminal 300 may determine whether the distance between the firstterminal 100 and the second terminal 300 is greater than or equal to afirst critical value.

If the distance between the first terminal 100 and the second terminal300 is greater than or equal to the first critical value (S3930-Y), thefirst terminal 100 or the second terminal 300 may determine whether thedistance between the first terminal 100 and the second terminal 300increases at a speed greater than or equal to a second critical value inan operation S3940.

If the distance between the first terminal 100 and the second terminal300 increases at a speed greater than or equal to the second criticalvalue (S3940-Y), the first terminal 100 may back up data of the firstterminal 100 in an operation S3950. For example, the first terminal 100may store data (content data or application data) being executed on thefirst terminal 100 and data being input to the first terminal 100 by auser to the storage 170 of the first terminal 100. Alternatively, thefirst terminal 100 may provide the above-stated data to the secondterminal 300 or an external device (e.g., a cloud device).

FIG. 40 shows an exemplary embodiment corresponding to the case in whichthe first terminal 100 is a mobile phone and the second terminal 300 isa wearable device that may be worn on a wrist of a user 4010. In FIG.40, if the user 4010 drops the first terminal 100, a distance 4020between the first terminal 100 and the second terminal 300 may rapidlyincrease. If the distance 4020 between the first terminal 100 and thesecond terminal 300 increases at a speed greater than or equal to thesecond critical value, the first terminal 100 may back up data of thefirst terminal 100 to prevent loss of the data.

In an operation S3960, the first terminal 100 or the second terminal 300may determine at least one of a first state and a second state. Next, inan operation S3970, the first terminal 100 or the second terminal 300may determine whether the first terminal 100 is dropped on the groundbased on at least one of the first state and the second state. If thefirst terminal 100 is determined to be dropped (S3970-Y), the secondterminal 300 may display a notification message indicating that thefirst terminal 100 is dropped, in an operation S3970. For example, asshown in FIG. 41, the user 4010 drops the first terminal 100 on theground, the first state indicates that the first terminal 100 is droppedon the ground and a particular amount of shock is applied to the firstterminal 100, and the second state indicates whether the user 4010possessing the second terminal 300 is moving. In this case, the firstterminal 100 may determine that the user 4010 dropped the first terminal100 and transmit a notification message indicating that the user 4010dropped the first terminal 100 to the second terminal 300.Alternatively, the second terminal 300 may determine that the user 4010dropped the first terminal 100 and display a notification messageindicating that the first terminal 100 is dropped.

One or more exemplary embodiments may be implemented by acomputer-readable recording medium, such as a program module executed bya computer. The computer-readable recording medium may be anon-transitory computer-readable recording medium. The computer-readablerecording medium may be an arbitrary available medium accessible by acomputer, and examples thereof include all volatile media (e.g., RAM)and non-volatile media (e.g., ROM) and separable and non-separablemedia. Further, examples of the computer-readable recording medium mayinclude a computer storage medium and a communication medium. Examplesof the computer storage medium include all volatile and non-volatilemedia and separable and non-separable media, which have been implementedby an arbitrary method or technology, for storing information such ascomputer-readable commands, data structures, program modules, and otherdata. The communication medium typically include a computer-readablecommand, a data structure, a program module, other data of a modulateddata signal, or another transmission mechanism, and an example thereofincludes an arbitrary information transmission medium. For example, thecomputer-readable recording medium may be ROM, RAM, a flash memory, aCD, a DVD, a magnetic disk, or a magnetic tape.

While one or more exemplary embodiments have been particularly shown anddescribed, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the inventive concept as definedby the following claims and their equivalents. Hence, it will beunderstood that the exemplary embodiments described above are notlimiting to the scope of the inventive concept. For example, eachcomponent described as a single unit may be executed in a distributedmanner, and components described distributed may be executed in anintegrated form.

The scope of the inventive concept is indicated by the claims and theirequivalents which will be described in the following rather than thedetailed description of certain exemplary embodiments, and it should beunderstood that the claims and all modifications or modified forms drawnfrom the concept of the claims and their equivalents are included in thescope of the inventive concept.

What is claimed is:
 1. A first electronic device for operating in an information protection mode, the first electronic device comprising: a communicator configured to communicate with a second electronic device; and a controller configured to, based on a signal strength of a signal transmitted to the second electronic device by the communicator or a signal strength of a signal from the second electronic device received by the communicator, control the first electronic device to operate in the information protection mode.
 2. The first electronic device according to claim 1, wherein the controller is further configured to, when the first electronic device operates in the information protection mode, control operations of the first electronic device based on state information of the first electronic device and state information of the second electronic device.
 3. The first electronic device according to claim 1, wherein the controller is further configured to, when the first electronic device operates in the information protection mode and in response to an attempt to unlock the first electronic device, control the communicator to transmit a notification of the attempt to unlock the first electronic device.
 4. The first electronic device according to claim 1, wherein the second electronic device comprises a wearable device, and the controller is further configured to, in response to a determination that the wearable device is not being worn by a user, end a communication between the communicator and the wearable device.
 5. The first electronic device according to claim 2, wherein the state information of the first electronic device corresponds to movement of the first electronic device, and the state information of the second electronic device corresponds to movement of the second electronic device.
 6. A non-transitory computer-readable medium having stored thereon instructions executable by a first electronic device to cause the first electronic device to perform: controlling to communicate with a second electronic device by a communicator; and controlling to operate in an information protection mode based on a signal strength of a signal transmitted to the second electronic device by the communicator or a signal strength of a signal from the second electronic device received by the communicator. 